TWI439566B - Method for using apparatus configured to form germanium-containing film - Google Patents

Description

Method of using a device for forming a ruthenium film [Cross-reference related application]

The present application claims the priority of the following: Japanese Patent Application No. 2009-036831, filed on Jan. 19, 2009, filed on

The present invention relates to a method of using a film forming apparatus in a semiconductor process for forming a Ge-containing film on a target article such as a semiconductor wafer. The term "semiconductor process" as used herein includes various processes for forming a semiconductor element on a target object or having a connection to a semiconductor element by forming a semiconductor layer, an insulating layer, and a conductive layer having a predetermined pattern on the target object. A structure of a wiring layer, an electrode, or the like; the target object may be, for example, a semiconductor wafer or a glass substrate for an FPD (Planar Display) such as an LCD (Liquid Crystal Display).

For example, the material of a conventional transistor gate electrode is polysilicon. When biased, the gate electrode of the polysilicon is easily depleted. This phenomenon, when the thickness of the gate insulating film is reduced, will have a significant influence and become one of the causes of deterioration of the component properties. In order to solve this problem, in the past studies, strontium was replaced by hydrazine having a higher dopant activation rate. In the past studies, 矽锗 was also used in other components such as diodes. For example, Japanese Laid-Open Patent Publication No. 2003-77845 discloses a method of forming a ruthenium film on a surface of a semiconductor wafer. This method employs a vertical heat treatment apparatus which supplies a monodecane (SiH ₄ ) gas and a monodecane (GeH ₄ ) to form a ruthenium film by CVD (Chemical Vapor Deposition).

In one example, a vertical heat treatment device is used to form a tantalum film on a first batch of wafers, followed by another film such as a tantalum film on a second batch of wafers. In general, the enthalpy contained in the process gas used in the aforementioned thermal process may be a contaminant for a film (such as a ruthenium film) formed in a subsequent thermal process. If the ruthenium is mixed in the ruthenium film, the component properties may deteriorate.

If the subsequent thermal process is a ruthenium film formation process, a so-called "pre-coating" process is performed to cover the inner surface of the reaction vessel or the like with a precoat film before the ruthenium film formation process. The precoat film prevents ruthenium from being dispersed into the process environment from the by-product film deposited in the reaction vessel, while the by-product film contains ruthenium as a main component (that is, it accounts for 50% or more).

However, as described below, the inventors have found that a conventional method of using a film forming apparatus in such a semiconductor process has room for improvement in terms of problems associated with ruthenium contamination.

SUMMARY OF THE INVENTION An object of the present invention is to provide a film forming apparatus for a semiconductor process which reliably solves the problem of contamination of germanium.

According to a first embodiment of the present invention, there is provided a method of using a device for forming a ruthenium-containing film, comprising: performing a first film formation process to chemically gas a product target object placed in a reaction vessel Phase deposition to form a first product film containing ruthenium. In the first film formation process, a cerium source gas is supplied into the reaction vessel, and the inside of the reaction vessel is heated, thereby activating the ruthenium source gas. Wherein the first film formation process produces a film-forming by-product deposited in the reaction vessel and containing ruthenium; after the first film formation process, performing a first cleaning process to etch the film to form by-products, at the first In the cleaning process, the first cleansing gas is supplied from the reaction vessel in which the product target object is not placed, the first cleaning gas containing halogen is supplied into the reaction vessel, and the inside of the reaction vessel is heated, thereby activating the first cleaning. a gas; after the first cleaning process, performing a second cleaning process to remove residual ruthenium from the reaction vessel, in which no product is placed from the inside Exhausting the reaction vessel of the target member, supplying a second cleaning gas containing oxidizing gas and hydrogen into the reaction vessel, and heating the interior of the reaction vessel, thereby activating the second cleaning gas, wherein the oxidizing gas system Selecting from a group consisting of oxygen, ozone gas, and nitrogen oxide gas; and after the second cleaning process, performing a second film forming process to isolate the product placed in the reaction vessel The target object is subjected to chemical vapor deposition to form a second product film containing no antimony. In the second film formation process, a film forming process gas is supplied into the reaction vessel, and the inside of the reaction vessel is heated, This activates the film to form a process gas.

According to a second embodiment of the present invention, there is provided a method of using a device for forming a ruthenium containing film, the device comprising: a reaction vessel for accommodating a plurality of target objects spaced apart in a vertical direction; a support member, For supporting the plurality of target objects in the reaction vessel; a heater disposed around the reaction vessel for heating the plurality of target objects; an exhaust system for exhausting from the reaction vessel; a gas supply a system for supplying a helium source gas, a helium source gas, and a gas for cleaning the inside of the reaction vessel into the reaction vessel, and a control portion for controlling operation of the device; the method comprising: performing first film formation a process for forming a first product film containing ruthenium by chemical vapor deposition on a product target object placed in the reaction vessel, wherein the ruthenium source gas and the ruthenium source gas are formed in the first film formation process The helium source gas is supplied into the reaction vessel and heats the interior of the reaction vessel, thereby activating the helium source gas and the helium source gas, wherein the first film is formed Forming a film-forming by-product deposited in the reaction vessel and containing ruthenium; after the first film formation process, performing a first cleaning process to etch the film to form by-products, in the first cleaning process, Internally, there is no exhaust gas in the reaction vessel in which the product target object is placed, a first cleaning gas containing fluorine and hydrogen is supplied into the reaction vessel, and the inside of the reaction vessel is heated, thereby activating the first cleaning gas; After the first cleaning process, a second cleaning process is performed to remove residual ruthenium from the reaction vessel, and in the second cleaning process, exhausting from the reaction vessel in which no product target object is placed inside, a second cleaning gas of oxidizing gas and hydrogen is supplied into the reaction vessel, and the interior of the reaction vessel is heated, thereby activating the second cleaning gas, wherein the oxidizing gas system is selected from the group consisting of oxygen, ozone gas and nitrogen a group of oxygen compound gases; and after the second cleaning process, performing a second film forming process to pass the product target object placed in the reaction vessel Chemical vapor deposition to form a second product film containing antimony but no antimony. In the second film formation process, the helium source gas is supplied into the reaction vessel, and the inside of the reaction vessel is heated. The helium source gas is activated.

Other objects and advantages of the invention will be set forth in the description which follows. The objects and combinations particularly pointed out herein can achieve the objects and advantages of the present invention.

The present inventors have studied the problem of the conventional method of using a film forming apparatus in a semiconductor process in the course of developing the present invention. The inventors obtained the following results.

As described above, when the vertical heat treatment apparatus is used to form the tantalum film on the first batch of wafers, and then the tantalum film is formed on the second batch of wafers, the precoating is performed immediately before the second batch of processes are performed. The cloth is processed to cover the inner surface of the reaction container with a ruthenium film or the like. However, the process temperature for forming a ruthenium film by thermal CVD is lower than the process temperature for forming a polysilicon film by thermal CVD. Therefore, at a lower temperature position, such as in the vicinity of the loading crucible formed at the bottom of the reaction vessel and thus far from the heater, the polysilicon film may be insufficiently formed and cannot be covered at these locations. A by-product film as a main component.

On the other hand, when a by-product film containing cerium oxide or tantalum nitride as a main component deposited in a reaction container is removed, a cleaning gas containing a halogen (e.g., fluorine) is supplied into the reaction vessel to perform the auxiliary Etching of the product film. However, if the by-product film contains ruthenium as a main component, even if it is etched like fluorine gas, ruthenium remains on the inner surface of the reaction vessel and remains on the surface of the boat.

Accordingly, conventionally, when a vertical heat treatment apparatus is used to form a ruthenium film on the first batch of wafers, and then a ruthenium film is formed on the second batch of wafers, a pre-process is performed between the secondary film formation steps. The coating process is carried out without performing the steps of etching and removing the by-product film containing ruthenium as a main component. It should be noted that even if the pre-coating process is performed after the step of etching and removing by-products, at a position where the temperature is lower, such as at a position around the loading crucible where the polycrystalline germanium film is insufficiently formed, it is not sufficiently covered. Residual defects.

Therefore, the inventors have looked at it from another angle and repeated experiments to reliably remove such residual ruthenium, and the inventors have found that active materials of oxidizing gas and hydrogen can be effectively used in this removal process. Although the inventors do not know the relevant documents relating to such residual sputum removal techniques, reference may be made to the following documents: Japanese Laid-Open Patent Publication No. 2008-283126 (paragraphs [0030] to [0031]; Figs. 1, 2), It discloses a method of removing a metal (such as copper) contained in quartz as a material of a reaction vessel. According to this method, a cleaning gas is first supplied into the reaction vessel to remove the by-product film, thereby exposing the quartz inner surface of the reaction vessel. Next, hydrogen and oxygen are supplied into the reaction vessel to remove the metal contained in the quartz surface by the radicals of the gases.

The embodiments of the invention based on the above findings are described and reference is made to the accompanying drawings. In the following, constituent elements having substantially the same functions and configurations will be denoted by the same component symbols; and the description will be repeated only when necessary.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional side view of a vertical heat treatment apparatus (film formation apparatus) according to an embodiment of the present invention. This vertical heat treatment apparatus 1 is designed as a film forming apparatus for forming a tantalum film (SiGe film) and a tantalum film (Si film) by thermal CVD.

As shown in Fig. 1, a heat treatment apparatus (film formation apparatus) 1 includes a columnar reaction vessel 2 which is made of, for example, quartz and is erected. The reaction vessel 2 has an opening at the bottom to form a loading crucible 21, and the flange 22 is integrally formed around the loading crucible 21. The cover 23 is made of, for example, quartz, disposed below the reaction vessel 2, so that the cover 23 comes into contact with the bottom of the flange 22, and the load port 21 is hermetically closed. The cover 23 is opened and closed by the boat lift (not shown) up and down. The shaft 24 extends through the center of the cover 23 and supports the substrate support or boat 25 at the top.

The boat 25 includes three or more (e.g., four) brackets 26. The bracket 26 has grooves (slots) for supporting a plurality of (e.g., 125) target objects or semiconductor wafers W in a spaced manner. The 125 wafers W are composed of a spacer disposed on the top side and the bottom side, and a product wafer disposed between the sides. The bottom of the rotating shaft 24 is connected to the motor M for rotating the rotating shaft 24, so that the boat 25 is rotated by the motor M. The thermal insulation unit 27 is disposed on the cover 23 around the rotation shaft 24.

An exhaust port 4 is formed at the top of the reaction vessel 2 for exhausting the inside of the reaction vessel 2. The exhaust port 4 is connected to an exhaust line provided with a vacuum pump 41 and a pressure control mechanism 42 to evacuate the inside of the reaction vessel 2 to a desired degree of vacuum. The furnace 3 is disposed around the reaction vessel 2 and includes a heater 31 for heating the inside of the reaction vessel 2. The heater 31 is formed of a carbon wire heater which enables the process to be performed in a minimally polluted (i.e., highly clean) environment and allows the temperature to rise and fall rapidly.

Each of the first to third injectors 51-53 has an L shape, is disposed to extend through the flange 22 at the bottom of the reaction vessel 2, and is used to supply process gas to the wafer W in the reaction vessel 2. In Figure 1, three injectors 51-53 are shown for insertion of the flange 22 at the same location for convenience. However, in fact, the injectors 51-53 are disposed side by side in the annular direction of the flange 22 at equal intervals, and are concentrated in an area in the annular direction to bring them close to each other for profit maintenance.

The injectors 51 to 53 have different lengths, and the gas supply ports at the ends (tip openings) are set at different heights. For example, the end of the shortest first injector 51 is provided near the bottom layer of the range in which the wafer W is supported in the wafer boat 25. As another example, the intermediate length second injector 52 is disposed slightly below the middle layer of the range in which the wafer W is supported in the wafer boat 25. As another example, the end of the longest third injector 53 is disposed between the top layer of the range in which the wafer W is supported in the wafer boat 25 and the end of the second injector 52. The injectors 51 to 53 are not limited to the configuration as shown in Fig. 1, and the length thereof is appropriately set in accordance with experimental results and the like.

The proximal ends of the injectors 51 to 53 extend beyond the flange 22 and are connected to the gas supply lines 61 to 63, that is, the gas supply pipes, respectively. The proximal end of the gas supply line 61 is connected to the gas supply lines 61a and 61b. The proximal end of the gas supply line 62 is connected to the gas supply lines 62a and 62b. The proximal end of the gas supply line 63 is connected to the gas supply lines 63a and 63b. The gas supply lines 61a, 62a, 63a are connected to a supply source 64 of a decane gas such as monodecane gas (SiH ₄ gas). The gas supply lines 61b, 62b, 63b are connected to a supply source 65 of a decane gas such as a monodecane gas (GeH ₄ gas). In this embodiment, the monodecane gas is a gas diluted to 10% with hydrogen.

The gas supply lines 61a, 62a, 63a supplying the monodecane gas are respectively provided with mass flow controllers M11 to M13 as flow regulators on the lines, and valves V11 to V13. The gas supply lines 61b, 62b, 63b supplying the monodecane gas are respectively provided with the mass flow controllers M21 to M23 located on the lines, and the valves V21 to V23. For each of the mixed gases supplied from the injectors 51 to 53, it is possible to adjust the flow rates of the monodecane gas and the monodecane gas independently of each other.

Further, an L-shaped injector 54 is disposed to extend through the flange 22 at the bottom of the reaction vessel 2 and to supply a cleaning gas into the reaction vessel 2. The cleaning gas system is for removing a by-product film of a reaction product which is generated at the time of film formation and deposited in the reaction vessel 2, wherein the by-product film contains as a main component (i.e., 50% or more) depending on the type of film formation. SiGe or Si. The gas supply port of the end of the injector 54 (tip opening) is provided near the bottom layer of the range in which the wafer W is supported in the wafer boat 25.

The proximal end of the injector 54 extends beyond the flange 22 and is connected to the gas supply line 71. The cleaning gas supply line 71 is connected to the supply source 74 of the halogen-containing gas via the valve V5 and the mass flow controller M5. For example, the gas supply source 74 is used to supply a halogen acid gas such as a fluorine (F ₂ ) gas or a hydrogen fluoride (HF) gas. In this embodiment, fluorine gas is used as the halogen-containing gas, and for convenience, the gas supply source 74 is shown in Fig. 1 as having the symbol of F ₂ .

Further, the cleaning gas supply line 71 is connected to the supply source 72 of hydrogen (H ₂ ) gas via the valve V3 and the mass flow controller M3. The cleaning gas supply line 71 is also connected to a supply source 73 of nitrous oxide (N ₂ O) gas, which is one of the oxidizing gases, via the valve V4 and the mass flow controller M4. The gas supply sources 72, 73 are connected to the cleaning gas supply line 71 via the gas mixer 70, and are supplied to the cleaning gas supply line 71 in a state where the hydrogen gas and the nitrous oxide are sufficiently mixed. Further, the cleaning gas supply line 71 is connected to the supply source 75 of nitrogen gas via the valve V6 and the mass flow controller M6.

Accordingly, the cleaning gas supply line 71 can selectively supply a predetermined flow rate of fluorine gas, hydrogen gas, nitrous oxide gas, and nitrogen gas. In this embodiment, a mixture of fluorine gas and nitrogen gas, or a mixture of fluorine gas, hydrogen gas, and nitrogen gas is used as a first cleaning gas for etching a by-product film containing SiGe as a main component; as for hydrogen gas and oxidized carbon dioxide A mixture of nitrogen gas is used as a second cleaning gas to remove residual germanium (Ge).

In detail, in the vertical heat treatment apparatus 1, a SiGe film is first formed by a thermal process, and then a Ge-free film such as a Si film is formed by a thermal process. Prior to the latter thermal process, a by-product film containing SiGe as a main component is etched with a first cleaning gas, and then a residual cleaning gas (Ge) is removed from the reaction vessel 2 with a second cleaning gas.

In this embodiment, the first and second cleaning gases are supplied into the reaction vessel 2 through the common line 71 and the injector 54. However, the first and second cleaning gases may each be supplied into the reaction vessel 2 through a dedicated supply line and injector.

Further, the vertical heat treatment apparatus 1 includes a control unit 8 for controlling the operation of the heater 31, the pressure control mechanism 42, the gas supply sources 64, 65, 72, 73, 74, 75, and the like. The control unit 8 includes a computer, such as a storage unit including a CPU and a storage program. The program includes a set of steps (instructions) for controlling the vertical heat treatment apparatus 1 to perform various operations required to perform film formation on the wafer W and to clean the inside of the process vessel 2. For example, the program is stored on a storage medium such as a hard disk, a compact disc, a magnetic optical disc, or a memory card, and is installed from a storage medium to a computer.

Next, an example of the method of using the above vertical heat treatment apparatus 1 will be described. First, a predetermined number of wafers W are placed, stacked on the wafer boat 25 at intervals, and then the wafer boat 25 is moved upward by a boat elevator (not shown). After this operation, the boat 25 is loaded into the reaction vessel 2, and the loading port 21 of the flange 22 is closed by the cover 23 (the state of Fig. 1 is shown).

Next, the inside of the reaction vessel 2 is evacuated through the exhaust line by the vacuum pump 41, and the process area in which the wafer boat 25 is located is adjusted to have, for example, 10 to 130 Pa (133 Pa = 1 Torr) by the pressure control mechanism 42. Vacuum environment. Further, the reaction vessel 2 is heated by the heater 31 to stabilize the process zone at a process temperature of, for example, 300 to 650 °C. Next, monodecane gas, monodecane gas is supplied from the supply sources 64, 65, respectively, and mixed by the gas supply lines 61 to 63 and the injectors 51 to 53. Next, the mixed gas is supplied from the end of the injectors 51 to 53, respectively, to the process zone in the reaction vessel 2 (Fig. 2A).

The injectors 51 to 53 are set with process gases of different mixing ratios, namely monodecane gas and monodecane. The mixing ratio of the injector 51 was set to: [monodecane gas] / [monodecane gas] = 1,200 sccm / 600 sccm. The mixing ratio of the injector 52 was set to: [monodecane gas] / [monodecane gas] = 300 sccm / 190 sccm. The mixing ratio of the injector 53 was set to: [monodecane gas] / [monodecane gas] = 300 sccm / 220 sccm. In other words, according to this embodiment, if the position of the injector supplying helium is high, the ratio of monodecane gas to monodecane gas ([monodecane gas] / [monodecane gas]) in the mixed gas is set to be relatively higher. low. It should be noted that, as above, the monodecane gas in this embodiment is a monodecane gas diluted with hydrogen to 10%.

The monodecane gas and the monodecane gas thus supplied react with each other after thermal decomposition in the process zone, whereby a SiGe film (ruthenium film) is formed on the surface of the wafer W. During the film formation, the wafer boat 25 is rotated by the motor M to form a uniform SiGe film on the surface of each wafer W.

It should be understood that the activation energy of monodecane is low and its decomposition reactivity is thus high. If only monodecane is supplied from the bottom to the reaction vessel 2, there will be less monodecane in the upper half of the boat 25. Accordingly, the apparatus shown in Fig. 1 employs three injectors 51 to 53 which are different in height from each other. Therefore, the monodecane supplied from the injectors 52 and 53 can compensate for the shortage of monodecane supplied from the lower injector 51.

The monodecane gas is premixed with the monodecane gas system, and then supplied into the reaction vessel 2 via the injectors 51 to 53, instead of being supplied separately from each other. When monodecane is supplied to the process zone, it has been diluted with monodecane; monodecane has a higher activation energy and thus lower decomposition reactivity. In this example, monodecane is used to prevent monodecane from causing an excessive decomposition reaction.

After the SiGe deposition is performed for a predetermined period of time, the supply of the process gas is stopped, and the inside of the reaction vessel 2 is replaced with an inert gas such as N ₂ gas. Next, the wafer boat 25 is removed from the reaction vessel 2.

During the formation of the SiGe film described above, a reaction product containing SiGe as a main component (i.e., 50% or more) is deposited on a surface of various components (e.g., reaction vessel 2, wafer boat 25) exposed to the supplied process gas atmosphere. on. The reaction product forms a by-product film on the surface of these elements and increases in thickness as the film formation process is repeatedly performed.

In this embodiment, as described above, the process of forming the SiGe film is performed on the first batch of wafers, and then the process of forming the Si film is performed on the second batch of wafers. Accordingly, the internal cleaning of the reaction vessel 2 is performed between the first batch and the second batch of wafer processes to prevent Ge contamination.

In detail, after the process of forming the SiGe film, the wafer boat 25 in the vacant state (ie, no wafer W is supported thereon) is loaded into the reaction vessel 2 which has been flushed by the N ₂ gas, and is covered with a cover 23 Close load 埠21. Next, while continuously discharging the gas from the reaction vessel 2, the first cleaning process and the second cleaning process are sequentially performed. The first cleaning process is performed to etch a by-product film containing SiGe as a main component in the reaction container 2. A second cleaning process is performed to remove residual Ge in the reaction vessel 2.

In the first cleaning process, the reaction vessel 2 is set such that the vacuum pressure therein is between 1064 and 199950 Pa, such as 13300 Pa, and the temperature is between 200 and 400 ° C, such as 300 ° C. Next, the first cleaning gas is supplied into the reaction vessel 2 from the cleaning gas supply line 71. For example, the first cleaning gas system is formed from a mixed gas of 2000 sccm of F ₂ gas and 8000 sccm of N ₂ gas, or F ₂ gas of 2000 sccm, H ₂ gas of 2000 sccm, and N _{2 of} 8000 sccm. a mixture of gases.

When the first cleaning gas is supplied to the heated reaction vessel 2, the mixed gas is activated, thereby generating fluorine radicals. These radicals etch and remove the by-product film present on the inner surface of the reaction vessel 2 and on the surface of various components (e.g., the boat 25 of Fig. 2B) in the reaction vessel. After the etching by-product film is thus performed for a predetermined period of time, the gas supplied into the reaction vessel 2 is changed from the first cleaning gas to the N ₂ gas to complete the first cleaning process.

Next, in the second cleaning process, the reaction vessel 2 is depressurized to a vacuum pressure of 13.3 to 931 Pa, preferably between 13.3 and 133 Pa, such as 46.55 Pa, and heated to its internal temperature. It is between 750 and 950 ° C, such as 850 ° C. Next, the second cleaning gas is supplied into the reaction vessel 2 from the cleaning gas supply line 71. For example, the second cleaning gas system is formed by a mixed gas of 1000 sccm of H ₂ gas and 1700 sccm of N ₂ O gas, or a mixed gas of H ₂ gas of 1700 sccm and 2000 cm of N ₂ O gas.

When the second cleaning gas is supplied into the heated reaction vessel 2, the mixed gas is activated, thereby generating hydrogen radicals and oxygen radicals. These radicals react with the residual Ge in the reaction vessel 2 and carry it into the gas, thereby discharging it out of the reaction vessel 2 (Fig. 2C). After the removal of the residual Ge is performed for a predetermined time (e.g., 5 hours), the gas supplied into the reaction vessel 2 is changed from the second cleaning gas to the N ₂ gas to complete the second cleaning process.

Next, when the empty boat 25 is still placed in the reaction vessel 2, the pressure and temperature in the reaction vessel 2 are adjusted to the conditions under which the Si film is formed, such as a pressure of between 13.3 and 133 Pa, such as 26.6 Pa, and the temperature. It is between 400 and 650 ° C, such as 620 ° C. Next, the monodecane gas from the supply source 64 is supplied into the reaction vessel 2 from the injectors 51 to 53 at a flow rate of, for example, 80 sccm to perform a precoating process to precoat the film (in this embodiment, a polycrystalline germanium film). Covering the inner surface of the reaction vessel 2, the surface of the boat 25, and the like (Fig. 3A). For example, the precoat process was performed for 100 minutes to form a 1 μm precoated film. After the second cleaning process, the pre-coating process is performed such that a trace amount of the metal element remaining on the surface of each element is covered by the pre-coating film, so that it is possible to prevent the Si film to be formed from being contaminated.

After the precoating process is completed, the wafer boat 25 is removed. In detail, nitrogen gas is supplied to the reaction tube 2 at a predetermined flow rate, and the pressure in the reaction vessel 2 is returned to the ambient pressure. Next, the cover 23 is moved downward, whereby the empty boat 25 is removed from the reaction vessel 2.

Next, another batch of a predetermined number of wafers W to form a Si product film are placed on the wafer boat 25, and are spaced apart in a stacked manner, and then the wafer boat 25 is lifted by a boat elevator (not shown). Move up. Under this operation, the boat 25 is loaded into the reaction vessel 2, and the loading port 21 of the flange 22 is closed by a cover 23 (the state of which is shown in Fig. 1).

Next, the inside of the reaction vessel 2 is evacuated by a discharge line by the vacuum pump 41, and the reaction vessel 2 is adjusted to have a vacuum environment by the pressure control mechanism 42. Further, the process zone in which the wafer boat 25 is disposed in the reaction vessel 2 is stabilized at the process temperature by the heater 31. Next, the monodecane gas from the supply source 64 is supplied from the injectors 51 to 53 into the process zone in the reaction vessel 2 (Fig. 3B).

When a polycrystalline tantalum film is formed as a Si product film, the process pressure is set to be between 13.3 and 133 Pa, such as 26.6 Pa, and the process temperature is set to be between 400 and 650 ° C, such as 620 ° C, and the monodecane gas is, for example, 300 sccm. Traffic supply. When an amorphous tantalum film is formed as a Si product film, the process pressure is set to 13.3 to 266 Pa, such as 26.6 Pa, and the process temperature is set to 300 to 570 ° C, such as 530 ° C, and the monodecane gas is, for example, 200 to 1000 sccm. Traffic supply.

The monodecane gas thus supplied is thermally decomposed in the process zone, whereby the Si film (Si product film) is formed on the surface of the wafer W. During the film formation, the wafer boat 25 is rotated by the motor M to form a uniform Si film on the surface of each wafer W.

After the Si deposition is thus performed for a predetermined period of time, the supply of the process gas is stopped, and the inside of the reaction vessel 2 is replaced with an inert gas such as N ₂ gas. Next, the wafer boat 25 is removed from the reaction vessel 2.

As described with reference to FIG. 2A to FIG. 3B, the above method for using the vertical heat treatment equipment 1 according to the embodiment of the present invention is used to sequentially perform the SiGe formation process, the first cleaning process, the second cleaning process, the pre-coating process, and the Si film. Form the process. In this sequence, the precoating process of the polysilicon film is performed at a temperature of, for example, about 620 ° C, and the SiGe film forming process is performed at a temperature lower than the precoating process, such as a temperature between 300 and 500 ° C.

For example, in the example of the control group, it is assumed that the order of the above processes is changed, so that the precoating process is performed after the first cleaning process, and the precoating process and the first cleaning process are not performed. Second cleaning process. In this case, as in the foregoing, in the lower temperature of the reaction vessel 2, such as near the loading enthalpy, the polycrystalline ruthenium film is insufficiently formed, so that the residual Ge cannot be sufficiently covered. Therefore, the Si film formed in the subsequent film formation process will be contaminated by Ge remaining at these positions.

Further, in the example as another control group, it is assumed that the order of the above-described processes is changed, so that the second cleaning process is performed before the first cleaning process. In this example, the by-product film containing SiGe as a main component deposited in the reaction vessel 2 is oxidized by the action of oxygen radicals, thereby forming an oxide film. The oxide film thus formed is hardly etched by the first cleaning gas, so etching and removing the by-product film becomes difficult.

For the above reasons, the order of the respective processes is preferably set according to the description with reference to FIGS. 2A to 3B.

In the above embodiment, N ₂ O gas was used as a gas for removing residual Ge in the second cleaning process. This is because, in general, form a vertical heat treatment apparatus comprising a Si film of N ₂ O gas supply line, and N ₂ O in the gas system used to dope Si O film, a Si film so that a smaller grain size impurities . However, other gases may be used as the oxidizing gas to remove residual Ge, such as oxygen, ozone gas or other nitrogen oxide gases (such as NO or NO ₂ ).

"experiment"

In the above vertical heat treatment apparatus 1, the method of using the example PE of the present invention according to the above embodiment, and the method of using the examples CE1, CE2, and CE3 of the control group are all performed to confirm the efficacy of the embodiment. The common point of the example PE of the present invention and the control examples CE1, CE2, and CE3 is that a film formation process is performed to form a SiGe film having a thickness of about 5 μm on the surface of the quartz substrate supported on the upper side and the lower side of the wafer boat 25. In the example PE of the present invention, the first and second cleaning processes are performed after the film forming process, in accordance with the sequence and conditions described with reference to Figs. 2A, 2B, in accordance with the following description. In the control examples CE1, CE2, CE3, after this film formation process, different processes were performed in the manner described below. Thereafter, the number of Ge atoms per unit area [quantity/cm ² ] remaining on the substrate was measured. The number of Ge atoms was measured by ICP-MS (Inductively Coupled Plasma Mass Spectrometer).

Control group example CE1

Performing wet cleaning: The quartz substrate on which the SiGe film was formed was immersed in a solution of hydrofluoric acid and nitric acid for several minutes.

Control group example CE2

Coating was performed: a polycrystalline germanium film having a thickness of 1 μm was coated on the surface of the quartz substrate.

Control group example CE3

The first cleaning process for etching the SiGe film is performed for about one hour: the first cleaning gas (F ₂ + N ₂ ) is supplied into the reaction vessel 2 containing the quartz substrate placed on the wafer boat 25.

Example PE of the present invention

The first cleaning process is performed as in the control example CE3; then the second cleaning process for removing residual Ge is performed for about five hours: the second cleaning gas (H ₂ + N ₂ O) is supplied into the containing and placed In the reaction vessel 2 of the quartz substrate on the wafer boat 25.

Experimental Results

Figure 4 shows the experimental results of the exemplary PE of the present invention and the control examples CE1, CE2, and CE3. In Fig. 4, the symbol T on the horizontal axis represents the measurement value of the substrate supported on the upper side of the wafer boat 25, and the symbol B represents the measurement value of the substrate supported on the lower side of the wafer boat 25. The vertical axis represents the number of Ge atoms measured [number / cm ² ].

Control Example CE1: Wet Etching

The number of Ge atoms measured on the substrate on the lower side of the wafer boat 25 is greater than 1.0 × 10 ¹² [number / cm ² ]. Accordingly, it was confirmed that the wet cleaning itself did not sufficiently remove Ge. Furthermore, the cleaning solution in the cleaning container is contaminated with Ge.

Control group example CE2: polycrystalline ruthenium film coating

The number of Ge atoms measured on the substrate on the upper side of the wafer boat 25 is more than 3.0 × 10 ¹² [number / cm ² ], and the number of Ge atoms measured from the lower substrate is more than 1.0 × 10 ¹¹ [number / cm ² ]. Accordingly, it has been confirmed that pre-coating is performed in a state where residual Ge remains, and it is difficult to achieve the effect of preventing Ge contamination.

Control group example CE3: first cleaning process

The number of Ge atoms measured on the substrate on the lower side of the wafer boat 25 is about 1.0 × 10 ¹¹ to 2.0 × 10 ¹¹ [number / cm ² ]. Accordingly, it was confirmed that this example did not fully achieve the effect of removing Ge.

Example PE of the present invention: first and second cleaning processes

The number of Ge atoms measured on the substrate on the lower side of the wafer boat 25 was about 3.0 × 10 ⁸ [number / cm ² ]. This value is close to the lower limit of the ICP-MS measurement range, so the effect of removing Ge is greatly improved compared to the control example. In detail, it was found that the first and second cleaning processes of the embodiments of the present invention can effectively prevent Ge contamination.

In this embodiment, the film forming apparatus used is a batch type processing apparatus having a single tube structure. However, by way of example, the present invention is applicable to a batch type processing apparatus having a dual tube processing vessel formed of an inner tube and an outer tube. Alternatively, the present invention can be applied to a batch type horizontal processing apparatus or a single substrate processing apparatus. The target substrate is not limited to the semiconductor wafer W, and may be a glass substrate such as an LCD.

Other advantages and modifications of the present invention will be immediately apparent to those of ordinary skill in the art. Therefore, the invention in its broader aspects is not limited to the specific details and embodiments described herein. Accordingly, various modifications may be made to the present invention within the spirit and scope of the invention as defined by the appended claims.

1. . . Vertical heat treatment equipment

2. . . Reaction vessel

3. . . furnace

4. . . Exhaust gas

8. . . Control department

twenty one. . . Loading 埠

twenty two. . . Flange

twenty three. . . Cover

twenty four. . . Rotating shaft

25. . . Crystal boat

26. . . support

27. . . Thermal insulation unit

31. . . Heater

41‧‧‧Vacuum pump

42‧‧‧Pressure control agency

51~54‧‧‧Injector

61~63‧‧‧ gas supply line

61a, 61b, 62a, 62b, 63a, 63b, 71‧‧‧ gas supply lines

64, 65, 72, 73, 74, 75‧ ‧ supply sources

70‧‧‧ gas mixer

M‧‧ motor

M3, M4, M5, M6, M11~M13, M21~M23‧‧‧ mass flow controller

V3, V4, V5, V6, V11~V13, V21~V23‧‧‧ valves

W‧‧‧ wafer

The embodiments of the present invention are described with reference to the drawings, and the description of

1 is a cross-sectional view showing a vertical heat treatment apparatus (film formation apparatus) according to an embodiment of the present invention.

2A, 2B, and 2C illustrate a method of using the device of Fig. 1.

3A and 3B illustrate a method of using the device of Fig. 1.

Figure 4 shows the results of an experiment for removing cockroaches using a method of use of a device in accordance with an embodiment of the present invention.

1‧‧‧Vertical heat treatment equipment

2‧‧‧Reaction container

3‧‧‧ furnace

4‧‧‧Exhaust gas

8‧‧‧Control Department

21‧‧‧Loading

22‧‧‧Flange

23‧‧‧ Cover

24‧‧‧ shaft

25‧‧‧The boat

26‧‧‧ bracket

27‧‧‧ Thermal insulation unit

31‧‧‧heater

41‧‧‧Vacuum pump

42‧‧‧Pressure control agency

51~54‧‧‧Injector

61~63‧‧‧ gas supply line

61a, 61b, 62a, 62b, 63a, 63b, 71‧‧‧ gas supply lines

64, 65, 72, 73, 74, 75‧ ‧ supply sources

70‧‧‧ gas mixer

M‧‧ motor

M3, M4, M5, M6, M11~M13, M21~M23‧‧‧ mass flow controller

V3, V4, V5, V6, V11~V13, V21~V23‧‧‧ valves

W‧‧‧ wafer

Claims (12)

A method of using a device for forming a ruthenium film, comprising: performing a first film formation process to form a first product film of ruthenium by chemical vapor deposition of a product target object placed in a reaction vessel In the first film forming process, SiH ₄ gas and GeH ₄ gas are supplied into the reaction vessel, and the inside of the reaction vessel is heated, thereby activating the SiH ₄ gas and the GeH ₄ gas, wherein the first The film forming process generates a by-product formed in the reaction vessel and containing ruthenium; after the first film formation process, performing a first cleaning process to etch the film to form by-products, in the first cleaning process Discharging the inside of the reaction vessel from which no product target object is placed, supplying a first cleaning gas containing fluorine gas into the reaction vessel, and heating the inside of the reaction vessel, thereby activating the first cleaning gas, The first cleaning process uses a process temperature between 200 and 400 ° C, and a process pressure between 1064 and 199950 Pa; after the first cleaning process, a second cleaning process is performed to remove the reaction Retaining the residual enthalpy in the apparatus, in the second cleaning process, exhausting the reaction vessel from the inside of the product object without the product target object, and supplying the second cleaning gas containing the oxidizing gas and the hydrogen into the reaction vessel, And heating the interior of the reaction vessel to thereby activate the second cleaning gas, wherein the oxidation gas system is selected from the group consisting of oxygen, ozone gas, and nitrogen oxide gas, and the second cleaning process uses 750 a process temperature between 950 ° C and a process pressure between 13.3 and 133 Pa; after the second cleaning process, a pre-coating process is performed to cover the inner surface of the reaction vessel with a ruthenium coating film, In the coating process, the SiH ₄ gas is supplied into the reaction vessel in which the product target object is not placed, and the inside of the reaction vessel is heated, thereby activating the SiH 4 gas; and after the precoating process, performing a second film forming process for forming a second product film of the ruthenium film by chemical vapor deposition of the product target object placed in the reaction container, in the second film forming process The SiH ₄ gas is supplied into the reaction vessel, and the inside of the reaction vessel is heated, thereby activating the SiH ₄ gas. A method of using a device for forming a ruthenium film according to claim 1, wherein the precoating process uses a process temperature higher than a process temperature of the first film forming process. A method of using a device for forming a ruthenium film according to claim 1, wherein the oxidizing gas of the second cleaning gas is an oxynitride gas. A method of using a device for forming a ruthenium film according to claim 1, wherein the first film forming process uses a process temperature between 300 and 650 ° C, and a process pressure between 10 and 130 Pa. A method of using a device for forming a ruthenium film, the device comprising a reaction vessel for accommodating a plurality of target articles spaced apart in a vertical direction, and a support member for supporting the plurality of target objects in the reaction vessel a heater disposed around the reaction vessel for heating the interior of the reaction vessel, an exhaust system for exhausting gas from the reaction vessel, and a gas supply system for discharging SiH ₄ gas, GeH ₄ gas, N ₂ O gas and gas for cleaning the inside of the reaction vessel are supplied into the reaction vessel, and a control portion for controlling the operation of the device, the method comprising: performing a first film forming process to be placed by the pair The product target object in the reaction vessel is subjected to chemical vapor deposition to form a first product film of the ruthenium film. In the first film formation process, the SiH ₄ gas, the N ₂ O gas, and the GeH _{4 are formed.} Gas is supplied into the reaction vessel, and the inside of the reaction vessel is heated, thereby activating the SiH ₄ gas and the GeH ₄ gas, wherein the first film formation process is deposited in the reaction vessel and contains ruthenium a film forming by-product of ruthenium; after the first film forming process, performing a first cleaning process to etch the film to form by-products, in the first cleaning process, the reaction container from which no product target object is placed Internal exhaust gas, supplying a first cleaning gas containing fluorine and hydrogen into the reaction vessel, and heating the inside of the reaction vessel, thereby activating the first cleaning gas, the first cleaning process using between 200 and 400 ° C Process temperature, and process pressure between 1064 and 199950 Pa; after the first cleaning process, performing a second cleaning process to remove residual ruthenium from the reaction vessel, in the second cleaning process, there is no internal Discharging the reaction vessel of the product target object, supplying a second cleaning gas containing oxidizing gas and hydrogen into the reaction vessel, and heating the interior of the reaction vessel, thereby activating the second cleaning gas, wherein the the oxidizing gas system of N ₂ O gas, the second cleaning process using the process temperature between 750 to 950 deg.] C, and the process pressure of 133 Pa to between 13.3; of the second cleaning process Performing a pre-coating process, using a silicon coating film to cover the inner surface of the reaction vessel, in which the pre-coating process, the SiH ₄ gas is supplied into the reaction vessel inside the target object is not placed in the product, and Heating the inside of the reaction vessel to thereby activate the SiH ₄ gas; and after the precoating process, performing a second film forming process to perform chemical vapor phase on the target product of the product placed in the reaction vessel Depositing to form a second product film of ruthenium. In the second film formation process, the SiH ₄ gas is supplied into the reaction vessel, and the inside of the reaction vessel is heated, thereby activating the SiH ₄ gas and using The N ₂ O gas is doped with O as an impurity in the ruthenium film to make the ruthenium film have a small crystal grain size. A method of using a device for forming a ruthenium film according to claim 5, wherein the precoating process uses a process temperature higher than a process temperature of the first film forming process. A method of using a device for forming a ruthenium film according to claim 5, wherein the first film forming process uses a process temperature between 300 and 650 ° C, and a process pressure between 10 and 130 Pa. A method of using a device for forming a ruthenium film according to claim 5, wherein the second film forming process uses a process temperature between 400 and 650 ° C, and a process pressure between 13.3 and 133 Pa. A method of using a device for forming a ruthenium film according to claim 1, wherein the oxidizing gas of the second cleaning gas is N ₂ O gas. The method for using a device for forming a ruthenium film according to claim 9, wherein the second film forming process comprises doping O in the ruthenium film with the N ₂ O gas as an impurity to crystallize the ruthenium film The particle size is small. A method of operating a heat treatment apparatus for heat treating a target object supported in a support and loaded in a reaction vessel provided with a heater, the method comprising: loading the target object into the reaction vessel, Supplying a process gas into the reaction vessel, and heating the reaction vessel with the heater to form a ruthenium film on the target object; and then removing the target object from the reaction vessel to supply a fluorine-containing cleaning gas into the reaction vessel In the reaction vessel, a membrane formed in the reaction vessel when the membrane is formed is removed from the reaction vessel; then an oxidizing gas and hydrogen are supplied into the reaction vessel, and the reaction vessel is heated, thereby activating the oxidation Gas and hydrogen, and removing ruthenium present in the reaction vessel by the activated oxidizing gas and hydrogen, wherein the oxidizing gas system is selected from the group consisting of oxygen, ozone gas and nitrogen oxide gas And then loading the target object into the interior of the reaction vessel, supplying process gas into the reaction vessel, and heating the counter with the heating device Container, to form another target object in the germanium film pollutants. The method of operating a heat treatment apparatus according to claim 11, wherein the membrane is a film of ruthenium as a contaminant.